Telegraph system



"March 14, 1939; M l. Pupm TELEGRAPH SYSTEM '4. sms-sheet .1

Filed July 9,'1956 @WSU ESR Tk mi ATTORNEYS .Marh 14,1939, MLPUPN-`2,150,781

TIELEGRAPH SYSTEM y @mi ATTORNEYS March 14, 1939.

TELEGRA'PH SYSTEM 4 Sheets-Shet 4 Filed Julyl 9, 1936 A'ITORNEYS VIi()Patented ai'o 14 i939 ausl Application if s, i936, eriai No. defied secrains. (et.

This invention relates to telegraph communication systems and has forits principal object the provision of an improved system or longdistance telegraphy.

The system may be employed in either land or submarine cable telegraphy,but is especially ape plicable to the latter because the problems andlimitations involved therein are much more severe than in the former. Itprovides a more perfect method of relaying than has heretofore beendeveloped and makes more emcient use of the cable by increasing thesignalling speed and reducing the time heretofore lost in synchronizingthe var ious units. In addition, the equipment is greatly simplified,thereby reducing the maintenance erf;-` pense and the number oi delaysdue to apparatus failures. The systemes a Whole is very reliable andcomparatively simple to operate.

The system may also be employed in teleg raphy by means of modulatedhigh frequency waves. When used in wireless telegraphy it oilers greatadvantages with regard to secrecy, and j,

therefore is very desirable to both comercial companies and to militaryforces. y

Broadly stated, the invention provides im proved transmitting or sendingapparatus for iin= pressing on a cable or other communication chan nel,such as a submarine cable or overhead or conf duit conductors in landtelegraphy, signal pulses having a definite, regular shape and uniformperiodicity. An alternating synchronizing voltage is impressed. on the'same cable for the purpose of effecting synchronisin between the send-ning and relaying units. over the cable or conductor a composite wavecomprising the alternating-synchronizing voltage with signal pulsessuperposed thereon.

When this waves arrives at the relaying station it is separated into itstwo components and the alternating voltage-used to drive a synchronouslyoperable relaying unit. This relaying unit funcn tions to completelyretransmit the received signal pulses, which are much distorted due tothe attenuation characteristic of the cable, in their original shape assent out from the sending stef1 tion.

As a primaryaid in securing more perfect relaying, and in increasing thespeed and reliability of the system as a. Whole, I provide a novelsignal reshaping or conforming unit. By means of this conforming unit itis possible to convert and translate a received signal yWave ofgreatlydistorted form into a series of signal pulses, each having a`deiinite, precise shape and the succession Aof pulses having e. uniformperiodicity. The

Thus there is transmitted pulses.

proper functioning oi this conforming unit depends upon only a portionof each received signal pulse and utilizes this portion to impress aconstant voltage of corresponding polarity across a timing circuit. Theportion of the signal pulse 5 so utilized is of denite duration and maybe preselected to be the most characteristic portion of the pulse, thatis, that portion having the maximum deviation from aero.

The timing circuit includes relay means actuf1'0 ated by the impressedvoltage for repeating the impressed signal pulses in their conformedshape, and a time delay circuit for continuing the actuation of therelay means a predetermined length of time after the voltage is removed.Th'eelec- -15 tromagnetic constants ci the time delay circuit may beproportioned so as to give repeated signal pulses of the desiredduration.

lIn order to select the desired portion of the v received signal pulses,`a contact'maker is pro- 20 vided which makes a uniform, continuousseries of contacts, with the interval between successive contacts equalto the interval between successive signal pulses, that is, theperiodicity of the series of contactsis the same as that of the signalpulse A2&5 intervals. The duration of each contact is the y same, and isequal 'to the predetermined fraction oi the signal pulse which it isdesired to utilize. This fraction may be chosen as desired, but 'asuitable value has been found to be one-fourth. 18 0 The contact makeroperates jointly with relay means responsive to the received signals toimpress the voltage across the timing circuit.

It will be apparent that the operation of the contact maker is such asto impress a. constant .'35 voltage of definite duration across thetiming cir-l cuit foreach received signal pulse, and that the voltagewill be impressed at uniform intervals equal to the, interval betweensuccessive signal l The magnitude and duration of this volt- 40 age isindependent of the received signal pulse, but the polarity is determinedby the polarity of the selected portion of the signal. Therefore, theduration ci successive contacts of the repeating relay means will beindependent of the received signal pulses, but the sequence of contactswill depend upon the corresponding polarities of the received signalpulses. The repeating relays may then be used to control the operationof apparatus for impressing corresponding signal 50 pulses on the cable.

'I'hus the relayed signal pulses will be of preoise shape and uniformperiodicity despite the severe distortion of the received signalsocca.-l sioned by the attenuation characteristic oi the ,65

2 cable, which markedly increases with the frequency an'd therefore cutsolf the higher harmonics in the signal wave.

. Another advantage of this method of relaying is its inherent stabilityof operation in the presence of electrical disturbances on theV cable,due to electrical storms, etc.. and its comparative freedom from theeffects of zero wende This is due to. the fact that the correctfunctioning of the relaying unit depends only upon the portion of thesignal pulse selected, and therefore it makes no diilerence what theshape of the incoming signal wave is,` solong as the selected portionsare of the correct polarity. Since these selected portions-may be chosenfrom the most characteristic part of the signal pulse, a maximumdeviation from the mean value of the signal train is permitted whilestill maintaining perfect relaying.

For the correct operation` of the conforming unit it is necessary thatthe contact maker operate in vsynchronism with the received signalpulses, and therefore in synchronism with the sending unit. At thepresent time a well-known method of synchronization is the clockhandcorrection method. The units at the various stations are driven orcontrolled by phonic wheel motors, each motorenergizcd With a directcurrent interrupted by a tuning fork. Since it is impossible to adjustthe several tuning forks to vibrate in exact synchronism over anextended period of time, the fork at the transmitting station isadjusted to run either slightly faster or slightly slower than those atthe other stations, and provision is made to restore periodically theunits to exact synclironism. Thus continuous synchronism is notmaintained hut, instead, there is a periodic progressive departuretherefrom, which'may be undesirable when high signalling speeds areemployed. Furthermore, this method of synchronization requires a tuningfork with associated corrective aptus at conch station, the frequency ofwhich must be carefully adiusted, and therefore introduces apparatuswhich is expensive, may get out of order, and requires considerable timefor correct synchronization after an idle period.

In the present system I provide apparatus for synchronization by meansof .a continuous alternating voltage sent over the same cable orcommunication channel as the message signals. This voltage is impressedon the cable by the transmitting unit, and the signal pulses superposedthereon. At the relaying station the synchronizing voltage is separatedfrom the signal pulsesby appropriate methods, preferably by a thermionicamplifier selectively tuned to the synchronizing frequency, and is usedto control the operation of a phonic wheel motor.

The composite wave is also passed into another channel which contains asubstantially distortionless amplifier. The synchronizing voltage may beeliminated from this channel by impressing thereon a voltage of likemagnitude and frequency but of opposite phase, by means of a voltagegenerator similar to the one at the transmitting station, or by anappropriate voltage obtained from the synchronizing voltage amplifier.

The received signal pulses so separated are used to control theoperation of the conforming unit in the manner hereinbefore described,and the contact maker of the unit ls driven by the synchronouslyrotating phonic wheel motor. The phonic motor also drives the signalpulse generating equipment controlled by the conforming escoger unit,for impressing corresponding signals on the cable to the receivingstation.

\ The conforming lunit is also useful at thereceiving station if it isdesired to record signals by automatic printing equipment, and in thatcase a synchronizing voltage is sent overl the cable from the relayingto the receiving station.

In a simplex system it is preferable to send out the synchronizingvoltage from the signal transmitting station and relay the voltage tothe receiving station, if desired, although it might be 4sent out fromthe relaying or receiving stations. In a duplex system the voltage maybe impressed on the cable at either terminal station and relayed to theother terminal statiini.4 'In either case all the synchronouslyoperating units are controlled by means of a single unit at one of thestations and operate in synchronism therewith, so that only a singletuning iorlr is required for the entire system. For this reason it isnot necessary to provide elaborate corrective apparatus to insure aconstant frequency, such as is required when two or more forks vibrateat slightly different frequencies.

Thus this method of synchronization has many advantages over previousmethods; it effects continuous synchronization of units separated by along cable, instead of a periodic progressive departure therefrom; itpermits controlling the units at the sending, relaying, and receivingstations by the use of, only a single tuning fork,

thereby eliminating apparatus which is expensive, may get out of order,and requires careful adjustment; and after the necessary adjustments aremade at the time of installation no further adjustments are required forsynchronizing the units after an idle period, thereby eliminating thetime required for synchronization by present methods.

Since the signal pulses areimpressed on 4the cable by the synchronouslyrotating apparatus, the frequency of the synchronizing voltage is alwaysdefinitely related to the signalling speed. The term signalling speed isa convenient way to designate the rapidity with which. successive signalpulses follow each other, and the phrase frequency of the signal pulsesmay be tal-zen to mean the frequency of e continuous succession ofsignal pulses. it will be apparent that the signalling speed, or thefrequency of the signal pulses; determines the speed with which anydesired sequence of signal pulses may be transmitted. The relativefrequencies and magnitudes of the synchronizing voltage and the signalpulses may be varied hetween wide limits but it has beenfound that asynchronizing voltage having one-foiuth the frequency and one-third themagnitude of the signal pulses is very satisfactory, although magnitudesvarying from onetenth to one and one-half times the signal pulses havebeen employed with success.

As is well known, an inherent limitation on the speed of signalling isthe attenuation characteristie of the cable, which markedlyincreaseswlth frequency. Due to this discriminatory eifect, signalpulses transmitted at too high a speed become practicallyindistinguishable, and are especially unsuited for automatic relaying.In order to enable the signals to he distinguishably received andtherefore make possible a higher signalling speed, I preferably employ'signal pulses conslstingof a marking pulse of desired' polarity followedby a curbing pulse of opposite polarity. The eilectof this curbing isvto define',

. so that in the received signal wave each pulse will appear as adecidedv hump. y Advantage is taken of this in relaying bys'electing thehump for the portion of the signal pulse which controls the conformingunit, therebyinsuring reliability and accuracy of operation, and freedomfrom small disturbances. The employment of curbed signals also preventscharging the cable by a succession of like signal pulses, and sominimizes zero Wander effects.

As a further als al improving the distinguishability of the signals, andthe reliability and precision of operation, l employ the above-describedconforming unit to control the signal pulse generating equipment at thetransmitting station.4

A tape transmitter is used for converting spaced code punchings in atelegraphic tape into electric current pulses of corresponding polarity.it is evident that if there is any irregularity in the size and spacingof the holes, or irregularity in the operation oi the tape transmitter,these pulses will not be of desired uniformity. Therefore the conformingunit is employed to insure impressing on the cable signal pulses-ofdednite,

circuit, including a battery, will be closed. When used with theconforming unit this transmitter gives excellent results and possessesthe great advantages of simplicity and reliability. The feeding of thetape, the operation of the conforming unit, and the operation of thesignal pulse generating apparatus are all controlled by the phonic wheelmotor at the transmitting station so that proper phase relations may bereadily maintained.

The following is a detailed description of a preferred embodiment of myinvention:

In the drawings, Fis. l is a schematic diagram showing the relationshipbetween the various units at the sending, relaying, and receivingstations;

ape; Fie. 3 is a side elevation of the tape transmitrating andamplifying the signal pulses and the synchronizing voltage at therelaying station;

Fig. 'l is a diagram to illustrate the advantages of using theconforming unit in relaying; and

Fig. 8 is a tabulation showing the wave forms found at various points inthe system for a given sequence of dots and dashes.

Referring to Fig. l, the various steps in the transmitting, relaying,and receiving of the message signals are shown in schematic form. Forpurposes of clearness, all electric ccnnectionsbe- Fis. 2 shows afragment of the telegraphic tween units are shown by a single, heavyline, y

and the units themselves are shown as separate and distinctpieces Aofapparatus with their rotating elements coupled together, although inpractice many of the units -will be combined. In the box representingeach unit, the gure is indicated in which a more detailed showing ofthat L unit may be found.v s

At the sending station the phonic motor drives the tape transmitter,which converts telegraphic tape punchings into corresponding .electricpulses; the conforming unit, which produces corresponding pulses ofdefinite shape and uniform periodicity; a signal pulse controller andgenere.- tor, controlled by these pulses and impressing corresponding`signalpulses on the cable; and a synchronizing voltage generator forimpressing that voltage on the cable.v

When the composite wave, comprising the sienal pulses and thesynchronizing voltage, reaches the relaying station it passes into twoamplifiersthe message channel amplifier, and the synchronizing channelamplier. The latter is selectively tuned to the frequency of thesynchronizing voltage and its output is used to `control the relayingphonic motor. This motor drives a synchronizing voltage eliminator whichbucles out that voltage from the message channel, thereby leaving onlythe signal pulses, which are then fed into a conforming unit andcompletely reshaped to their original form. 'These reshaped pulsescontrol a signal pulse controller and generator exactly'as at thesending station, and impress corresponding signals on the succeedingcable section. The relaying phonic motor also drives a synchronizingvoltage generator as at the sending station.

- At the receiving station the two components of the composite wave areseparated as at the relaying station, and a. conformingunit reshapesthe'signal pulses for operating recording appa.- ratus, such as anautomatic printer. Of course, ifa. siphon recorder is used it will notbe neces-- sary to reshape the received signals and the synchronizingvoltage need not be sent over the cable to the receiving station,thereby eliminating the corresponding apparatus.

Fig. 2 shows a fragment of telegraphic tape Ill which may be used totransmit'messages by the International Cable Code, in which a pulse ofcurrent in one direction, say positive, signifies adot, and a pulse ofcorresponding duration but of opposite polarity, a dash. The holes Ilreprewith holes I8 to feed the tape at the desired,

speed. Spring elements 2l! are fastened to 'a suitable support 2I andcarry at ltheir lower lends contact elements 22 and 23.. These contactelements press lightly on the tape t0 and are so positioned that whenholes Il or l2 pass thereunder the inner contact elements pass throughlthe holes and make contact with the drum il,

thereby completing a suitable circuit and'generating' a. correspondingpulse of current. Since itis customary to employ a tape which is waxedor parafdned, occasionally particles oi.' wax are caught between theinner contactelements and 'pressing on said channel a. continuousalternating voltage having a. frequency bearing a denite ratio tothefrequency of the signal pulses, a synchronousl-y operable relaying unitconnected to said channel, means for causing said voltage to maintainsaid relaying unit in continuous synchronism. therewith, and means forcontrolling the opera tion of said relaying unit by the signals receivedduring deilnite portions of the signal pulse inter-I vals, said relayingunit recreating signal pulses corresponding to those received duringsaid inter vals for retransmitting corresponding signals, the

said rreated signal pulses having ,definite .the frequency of the signalpulses bearing a denite ratio to that of the alternating voltage,

passing the impulses received at the other end oi said communicationchannel into two channels, selectively amplifying the alternatingvoltage in one of said channels to the substantial exclusion of thesignal pulses, utilizing said separated voltage to maintain the relayingunit in synchronism therewith, eliminating the alternating voltage inthe other of said channels by an equal and opposite voltage impressedthereon by means oi said separated voltage, and utilizing the signalpulses so separated to control the operation oi the relaying unit forretransmitting corresponding signals.

8. In a 'telegraph system including a sendingunit and a synchronouslyoperable relaying unit operativelyl connected to a communicationchannel, the method of transmission which comprises impressing on said'channel by said sending unit a continuous alternating voltage and signalpulses, the frequency of the signal pulses bearing a definite ratio tothat of the laternating voltage, passing the impulses received at theother end of said communication channel into two channels, selec:-tively amplifying the alternating voltage in oneoi said channels to thesubstantial exclusion of the signal pulses, utilizing said separatedvoltage to maintain the relaying unit in synchronism therewith,utilizing said synchronously operated unit to generate and impress avoltage in the other oi saidchannels substantially equal and opposite tothe alternating voltage contained therein, and utilizing the signalpulses so separated to con- 'trol the operation of the relaying unit forretransmitting corresponding signals.

9. In a telegraph system including a sending- A unit and a.synchronously operable relaying unit operatively connected to aycommunication channel, the method of transmission which comprisesimpressing on said channel by said sending unit a continuous alernatingvoltage and signal pulses,

the frequency of the signal pulses bearing a definite ratio to that ofthe alternating voltage, passing the impulses received at the other endof said,

-communication channel into two channels, selectively amplifying thealternating voltage in one of said channels to the substantial exclusionof the signal pulses, utilizing said separated voltage to europeimaintain the relaying unit in synchronism there# other of said channelsby an equal and opposite Voltage impressed thereon by means of saidseparated voltage, and utilizing the portions of the signals receivedduring only deilnite portions of the signal pulse intervals to controlthe operation of the relaying unit for retransmitting correspondingsignals.

l0. In a telegraph system including a sending unit and a synchronouslyoperable relaying unit operatively connected to a communication channel,the method oi transmission which comprises impressing on said channelloy said sending unit a continuous alternating voltage and signalpulses, the frequency of the signal pulses bearing a definite ratio tothat of the alternating voltage,

' passing the impulses received at the other end ci said communicationchannel into two channels, selectively amplifying the alternatingvoltage in one oi said channels to the substantial exclusion of thesignal pulses, utilizing said separated volt. age to maintain therelaying unit in synchronism therewith, utilising saidsynchronouslyoperated unit to generate and impress a voltage in theother oi said channels substantially equal and opposite to thealternating voltage Acontained therein, and utilizing the portions ofthe signals receved during only denite portions of the sign nal pulseintervals to control the operation of the relaying unit ,forretransmitting corresponding signals whose lengths are substantiallygreater than the said portions of the signal pulse intervals.

ll. in a telegraph system, apparatus ior reshaping signal pulsescomprising relay means responsive to said signal pulses, contact meansmalring a uniform series oi contacts having the perisaid contact means,a repeating relay having an actuating coil, said energizing circuitbeing adapted to energize said actuating coil when closed by the jointaction of said relay means and said con tact means, and means continuingactuation of said repeating relay for a preselected interval after saidcircuit is opened including a capacitance in parallel with saidactuating coil, said capacitance being charged by the closing of said.

energizing circuit and discharging through the actuating coil after theenergizing circuit is broken 'to continue the actuation of saidrepeating relay vfor said preselected interval.

l2. in a telegraph system, apparatus for re'- shaping signal pulsescomprising relay means responsive to said signal pulses, rotary contactmeans making a uniform series, o contacts having the periodicity of acontinuous succession of signal pulses, said contacts being oi equalduration lessthan that of a signal pulse interval, an

o energizing circuit under joint control of said relayy source ofvoltage under joint control of said receiving relay and said contactmaker for applying said voltage to the first-mentioned circuit when theenergizing circuit is closed by the closure of both receiving relay andcontact' maker and thereby actuating said repeating relay and chargingsaid capacitance, said voltage, resistance, inductance and capacitancebeing selected so that upon the opening of said energizing circuit thecapacitance will discharge through the actuating coil of the repeatingrelay and continue the actuation thereof for a selected intervalthereafter, thereby generating repeated signals which persist for saidselected interval,

14. In a telegraph system, a communication channel; Aa tape transmitterconverting telegraphic tape punchings into corresponding electric signalpulses; and transmitting means controlled `by means. of .only a portionof each of said pulsesv to impress corresponding signals on t pulses, acontact maker for making a uniform i said channel, saidtransmittingmeans comprisp ing a relay selectively responsive to saidsignal series of contacts having the periodicity of 'a continuoussuccession of signal pulses, said contacts being of equal durationsubstantially less than that of a signal pulse interval, an energizingcircuit under joint control of said relay and saidcontact maker, arepeating relay having an actuating coil energized upon closure of saidenergizing circuit by the joint action of said relay and said contactmaker, a repeating relay having an with the actuating coil of saidrepeating relay, said capacitance being charged by the closing of saidenergizing circuit and discharging through the actuating coil of saidrepeating relay after the energizing circuit is broken so as to continueactuation thereof for a selected interval after said circuit is broken',whereby signals which persist for said selected interval may begenerated.

15. In a telegraph system including a communication channel, means forimpressing upon said channel uniformr signal pulses which comprises afeeding mechanism for feeding a tape perforated in accordance with thesignal pulses which it is desired to transmit, a contact elementpositioned Y passing under said contact element, acontact. 'makercorrelated-with said feeding mechanism for making a uniform series ofcontacts-having the periodicity of the signal pulse intervals, saidcontacts being of equal duration substantially less than that of asignal pulse interval, an energiz- 1 ing circuit under joint control ofsaid relay and said conta-ct maker, a repeating relay having anactuating coil, said energizing circuit being .adapted to energize saidactuating. coil when closed by the joint action of said relay and saidbeing charged by the closing of said energizing circuit and dischargingthrough the actuating coil after the energizing circuit is broken tocontinue the actuation of said repeating relay for said selectedinterval.

l16. In a telegraph system including a' ccmmunication channel, means forimpressing upon said channel uniforml signal pulses which c'omprises afeeding mechanismfor feeding a tape perforated in accordance with thesignal pulses which it is desired to transmit, a contact' elementpositioned and constructed to continuously bear against a tape in saidfeeding mechanism,

a relay controlled by said contact' element so as A to be actuatedinac'cordance with the perforations in said tape passing under saidcontact element, a contact maker correlated with said feeding mechanismfor making a uniform series of contacts having the periodicity ofthe-signal pulse intervals, said contacts being of equal durationsubstantially less than that of a signal pulse interval, a repeatingrelay having an actuating coil, a capacitance in parallel with saidactuating coil', the circuit including said. 4capacitance and saidactuating coil having resistance, inductance "and capacitance, anenergizing circuit'including a source of voltage under Joint control ofthe first-mentioned relay and said contact maker for applying saidvoltage to the first-mentioned circuit when the energizing circuit isclosed by the closure of both the first-mentioned relay and the contactmaker and thereby actuating said repeating relay and charging saidcapacitance, said voltage, resistance, inductance and capacitance beingselected so that upon the opening of said energizing circuit thecapacitance will.

for receiving said signal pulses and synchronizing voltage at the otherend of said communication channel, means synchronized by the receivedsynchronizing voltage for selecting definite portions of the signalpulse intervals, and means i vcontrolled by the signals received duringthe said 'selected portions for recreating corresponding signals ofdefinite length substantially greater than the said selected.l portionsof the signal pulse intervals.

18. In a submarine cable telegraph system, in combination, means forimpressing on a submarine cable signal pulses and acontinuousalternating synchronizing voltage, the frequency of said synchronizingvoltage bearing a definite ratio to the frequency of the signal pulseintervals, means for receiving'said signal pulses and synchronizingvoltage at the other end of said cable, a contact maker synchronized bythe received synchronizing voltage for-making a uniform series ofcontacts having the periodicity of the signin pulse intervals, theduration of said contacts being substantially shorter than saidintervals, and asignal repeater under the joint control of the receivedsignal pulses and said contact maker for recreating signals.corresponding tothe signal portions received while said contacts aremade, the signals recreated by saidsignal repeater having lengthssubstantially greater than the duration of' said contacts.

19. In :a-submarine cable telegraph system, in combination,I means forimpressing on a submarine cable signal pulses and a continuousalternating synchronizing voltage, ,the frequency for making a uniformseries of contacts having the periodicity of the signal pulse intervals,the

duration oi said contacts being slibstaritially shorter than saidintervals, an energizing circuit under joint control `of said receivingrelay and said contact maker, arepeating relay having an actuating coilenergized upon closure of saidem1 ergizing circuit by the joint actionof said receiving relay and said contact maker, and a capacitance inparallel with the actuating coil,

of said repeating relay, said capacitance being charged by the closingof said energizing circuit and discharging through the actuating coil oflsaid repeating relay after the energizing circuit is broken so as tocontinue a tuation thereof for a selected interval after said circuit isbroken.

` 20. In a submarine cable telegraph system, in

combination, means for impressing on asub marine cable signal pulses anda continuous alternating synchronizing voltage, the frequency of saidsynchronizing voltage bearing a definite CERTIFICATE Patent No 2;, l50,781.,

ratio to the frequency of the signal pulse intervals, means forreceiving and separating said signal pulscsand synchronizing voltage atthe other end 'oi said cable, a receiving relay selectively responsiveto the received and separated signal pulses, a contactl makersynchronized by the received and separated synchronizing voltageformaking a uniform series of contacts having the periodicity ci the signalpuise intervals, said contacts being of equal durationsubstantially-less than that o a signal Apulse interval, a repeatingrelay having an actuating coil, a capacitance in parallel with saidactuating coil,

ythe circuit including said capacitance and saidv actuating coil havingresistance, inductance and capacitance, an energizing circuit includinga source of voltage under joint control of said receiving relay and saidcontact 4maker for applying' said voltage tothe first-mentioned circuit*when the ,energizing circuit is closed by the closure ci both saidreceiving relay and the contact maker and thereby actuating saidlrepeating relay and charging said capacitance, said voltage, resistance,inductance and capacitance being selected so that upon the opening oisaid energizing circuit the capacitance will'discharge through theactuating coil oi the repeating relay and continue the actuation thereoffor a. selected interval thereafter, thereby generating repeated signalspersisting for saidselected interval.

, venirmi ement si, Administratif@ of the Estate of Michael idwrslcyPapin, Deceased.

0F contractione e March lil, 1959 VARVARA PUPIN Sl'll'IH, ADMINISTRATRIXor MICHAEL IDvoRsKY PUPI'N, DEGEASED@ It is hereby certified that errorappears in the printed specification lofthe above numbered patentrequiring correction as follows: Pegel, first column, line 58, for theword "waves" read wave; page 5, first col, line "(5for "electric" readelectrical3 page 5, second column, line 8, for "wil" read will; page 6,first column, line )4.9, for message read'meesage; page 7 first column,line 65, claml, and second colmi-1n, line 6, claim`2, after"superpovsing" vinsert signal pulses; line 10,'claim 2 strike outvianciig page 8, first column, `line 11,9, claim8, for "laternating"read alternating; page 9, first column, line h2., claim llufor "arepeating relay having an" readand a capacitance in parallel; and thatthe.. said Letters Patent should. be

, read with this correction y,therein that the sarnemay conform to therecord` of thel case in the Patent office. y

signed and sealed this 9th day 'or Mama. D. 1959.

Henry Van Ar edele (Seal) Acting ,Commissionerof Patente.

